Study on Impact Factors and Scaling Effect of Spatial Distribution of Cr Content in Regional Soil

Chromium (Cr) is a typical toxic and hazardous heavy metal element. Its content in soil is closely related to natural conditions and human activities. Based on the data of Cr soil content, land use types, soil types, elevation and slope of Jiangning Economic and Technological Development Zone, the spatial correlation between Cr content in soil and various influencing factors is quantitatively studied using the principle of information entropy, and thus, the scaling effects are analyzed to identify the key factors for the distribution of Cr soil content at different spatial scales. The key factors affecting the distribution of Cr content in soil at different spatial scales are determined. The results show that at the large scale (over the Jiangning Economic and Technological Development Zone), the significance ranking of factors is land use type>soil type>elevation>slope; at the medium scale (the Niushoushan River basin scale), the order is elevation>slope>soil type>land use type; at the small scale (the tributary basin of Niushoushan River scale), elevation is most important, followed by soil type, slope, and land use type. This study can provide references for future decision-making on prevention and control of regional soil heavy metal pollution and for researches on the scaling effects of the key impact factors.